Visible-range and self-powered photodetectors with SnSe nanostructures: The influence of copper concentrations and ultrasound waves irradiation on optoelectronic performance

Recent studies on tin selenide (SnSe) nanostructures have primarily focused on their thermoelectric performance, with limited attention given to their optoelectronic potential. In this study, we investigate the physical and optoelectronic properties of SnSe nanostructures with varying concentration of Cu doping and exposure to ultrasound radiation. The results reveal that increasing the concentration of the dopant element and utilizing ultrasound irradiation not only led to reduced stress and strain but also led to an increase in crystallite size. For instance, crystallite size increased dramatically up to 8.96 nm and 17.54 nm for doping and radiation of ultrasound waves in comparison to the undoped SnSe, respectively. Field emission scanning electron microscopy (FESEM) results indicate the presence of nanorods accompanied by agglomerated particles dispersed throughout all samples. The extent of doping and the parameters related to ultrasound irradiation significantly influence the shapes of these nanostructures. Photoluminescence (PL) analysis demonstrates that these influential parameters cause shifts in emission bands and changes in their intensity. Absorption spectra measurements in the range of 200–1100 nm reveal an increase in absorption due to the influence of effective parameters. Furthermore, alterations in the optical energy band gap (E_g) indicate that it enhanced within the range of 1 to 1.68 eV. The I-V characteristics results show that these influential parameters contribute to the enhancement of responsivity (0.369 to 0.467 mA/W) and sensitivity (572% to 1826%). The specific detectivity ranges from 2.90 to 10.60 × 10⁺⁹ Jones. These effective parameters also have a favorable impact on mobility, ideality factor, and carrier concentration.